Pneumatic piano.



W. G. BETZ.

PNBUMATIG PIANO.

APPLIOATION rILBD APB. 11, 1910.

1,023,613. Patented Apr. 16, 1912.

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COLUMBIA PLANoanAPI-I co.. WASHINGTON. D. c.

W. G. BBTZ.

PNEUMATIC PIANO,

APPLlGATIoN FILED APR. 11, 1910.

Patented Apr. 16, 1912.

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ATTORNEY.

UNITED sTATEs PATENT oEEIoE.

WILLIAM G. BETZ, OF STEGER, ILLINOIS, ASSIGNOR TO STEGER & SONS PIANO MANU- FACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

PNEUMATIC PIANO.

To all whom` t may concern Be it known that I, WILLIAM G. BETZ, of Steger, county of Cook, and State of Illinois, have invented a certain new and useful Pneumatic Piano; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings.

The object of this invention is to improve the construction disclosed in my former application, Serial Number 528,689, tiled Nov. 1S, 1909.

One feature of this invention consists in mounting the primary valve construction immediately to the rear of and in close proximity with the secondary valve so as to simplify materially the device and reduce its size, and promote the quickness of its action.

Another feat-ure of the invention consists in means for readily adjusting the spring which controls the secondary valve.

Still another feature of this invention consists in means mounted in connection with the power pneumatic to limit the vibratory member thereof. This feature greatly improves the operation of the device, its quickness and accuracy and thus improves the quality of the music produced.

The nature of this invention will be understood from the accompanying drawings and the following description and claims.

In the drawings Figure 1 is a central vertical section transversely of the piano through the portion to which this invention relates on the line 1 1 of Fig. 2, parts being broken away andparts omitted. Fig. 2 is a front elevation of the left end of the portion of the piano to which this invention relates, with the right hand end broken away and with the parts removed. Fig. 3 is a reproduction of the lower part of Fig. 1 with the parts operating. Fig. 4 is a central transverse sect-ion through the secondary valve and parts connected therewith and with which the same is mounted.

In the drawings herein represents the key of a piano-forte having a capstan screw 11 in position to be engaged by a sticker 12 when permitted by a pivotally controlled` lever 13 which is fulcrumed between its ends to the lower end of the bar 14 extending down through the board 15 transversely of the piano and supporting the power pneumatics and the associated parts. A spring Specification of Letters Patent.

Application filed April 11, 1910.

Patented Apr. 16, 1912.

Serial No. 554,850.

16 mounted in connection with the board 15 tends to depress the inner end of the lever 13. The outer end of said lever is actuated or depressed by the connecting rod 17 which is secured to the plate 18 of the vibratory member 19 or plate of the bellows or power pneumatic.

Each power pneumatic consists of a stationary bottom plate 20, the inner portion of which is thickened and extends downwardly and through which a pin or screw 21 extends and enters the plate or board 22. The base 20, vibratory member 19 and side walls of the flexible connecting material 23 constitute a bellows and power pneumatic. These power pneumatics are arranged in hori- Zontal and vertical series. They are placed in staggered position vertically, as shown in Fig. 2, and therods 17 are varied in length so as to reach the desired power pneumatic. The rods 17 of the elements in each vertical series do not interfere with each other. In the base of each power pneumatic there is a passageway 25 leading from the rear end to a point about midway of the base. In each base 20 an adjustablev stop 26 is provided consisting of a screw with a felt head thereon projecting into the inner end of the power pneumatic in position to limit the contracting movement of the vibratory plate 19. Likewise there is an adjustable stop 27 secured to the bottom plate of the upper power pneumatic and to a horizontal board 28 to limit the upward movement of each vibratory plate 19. By these adjustable stops 26 and 27, the exact degree of Inovement of the vibratory plate 19 can be readily fixed so as to obtain the exact piano-forte action desired. A power pneumatic in operation is illustrated in Fig. 3, where it appears that the stop 26 has limited the Contracting movement of the plate 19, of the bellows.

The board 22 extends transversely of the piano and is secured at its bottom and top edges to the strips 30 and 31 which in turn are secured to a board 32 parallel with t-he board 22 and secured at the bottom to the cross piece 15 and at the top to the board 2S. The strips 30 and 31 form a chamber 33 with the two boards 22 and 32. The board 32 has funnel-shaped ports 34 and across the wider ends thereof pouches are secured. A disk 36 is secured to each pouch and has a stem 37 with an enlarged dished end which projects centrally into the port 38 in the plate 22 which leads from the chamber 33 to the valve chamber 39. This valve chamber has an upper enlarged portion, see Fig. 2, for a secondary valve 40. The valve chamber 39 has a lower contracted portion 139 which communicates with the passageway in the power pneumatic through the port 41 in the small square metal plate 42.

There is a metal plate 42 for each power pneumatic and screws 21 secure the plate 42 to the board 22 and also secure the power pneumatic to the plate 42. The plate 42 has also other screws 43 at the top as thatplate covers the secondary valve chamber 39 and it also has a circular opening in it with an annularly grooved wall in which a helical spring 44 ts. This spring centrally supports the stem 46 of the secondary valve 40 so that the inner end of said stem 46 projects loosely into the dished enlargement at the end of the stem 37 whereby endwise movement of either the stem 37 or 46 causes endwise movement of t-he other stem and yet they are not connected. A lug 47 from the outside of the secondary valve 40 spaces it away from the spring 44. The stem 46 is threaded for almost its entire length and valve 40 is secured so the valve can be adjusted thereon and a small nut 48 screws on t-he outer end of the stem for holding the stem atl the proper position in the spring 44. The stem 46 and nut 48 are accessible by long pliers when the bellows 19 are depressed and thereby the position of the stem 46 can be adjusted to bring about the proper action oit' the valve 40 and spring 44 and pouch disk 36.

The primary valve construction is secured to the rear surface of the board 32. It consists of a rear board 50 parallel with the plate 32 and extending transversely and a number of horizontal strips 51 and 52 are secured between plates 32 and 50. There is a pair of the plates 51 and 52 for each horizontal row of power pneumatics. Tubes 53 extend from the tracker bar (not shown) to the passageways or chambers 54 in the plate 50 and which are in communication through the port 55 with passageways 56 in the lower plates 52 that lead beneath the primary pouches 57 secured horizontally on the upper surface of the plates 52 for closing the upper end of the passageways 56. Between the strips 51 and 52 there is a chamber 58 containing the lower head ot each pair of primary valves 60, which primary valve consists of a cylindrical stem with a head on each end. The stem extends through a vertical passageway 61 in the strip 51 and the passageway is of larger' diameter than the stem portion of the primary valve but is of smaller diameter than the head of said valve. A port 62 leads from the passageway 61 to the secondary pouch port 34. The space 63 above each strip 51 is open to the outer air. The stem portion of the primary valve is longer than the thickness of the strip 51 and the lower head of the valve rests upon the primary pouch 57. Hence, when the primary valve is down, as shown in Fig. 1, there is communication between the chamber 58 through the passageway 61 and port 62 with the pouch port 34.

64 is a bleed hole.

The operation is as follows: Means are provided in the piano tor constantly exhausting the air from the chamber 33. This suction normally causes the secondary valve 40 to be closed, as shown in Fig. 1, but when the air enters through the tracker bar and passes through the tube to the passageway 56 under the pouch 57, the pressure ot' the air forces the primary valve upwardly so as to open communication with the outer air. The outer air will actuate the secondary pouch, as shown in Fig. 3, and cause the secondary valve 40 to be opened and then the air in the bellows or power pneumatic will be exhausted through the passageway 25, port 41, chamber 39, port 38 and suction chamber 33. This will cause the operation of the piano action. Vhen the air ducts in the tracker bar are closed, the parts will return to their normal position as shown in Fig. 1, and then the primary valves will descend and close the communication from the outside air with the secondary pouch port. The bleed hole 64 will equalize the air pressure on both sides of the primary pouches 57 and the suction in chamber 33 and atmospheric pressure on valves 40 will cause said valves 40 to close.

l claim as my invention:

1. In a pneumatic piano, the combination of a main suction chamber extending transversely of the piano, a plurality of primary suction chambers extending rearwardly therefrom and arranged one above the other and each in communication at intervals with said main suction chamber, a valve for controlling eacli communication between said suction chambers and the main suction chamber, a vertical plate extending transversely of the piano and secured to the rear sides of said suction chambers and provided with a vertically disposed passageway in communication with said primary suction chamber near each valve, and a-trackerboard connection with each of said vertically disposed passageways in said plate.

2. A pneumatic piano including a plurality of horizontal rows of power pneumatics one located above the other, a main suction chamber extending continuously throughout the length ot' the piano with separate communications therefrom with CIK each of said power pneumatics, a secondary valve controlling each of said communications, secondary pouches in the rear portion of said main suction chamber for actuating said secondary valves, a pouch port immediately to the rear of each of said secondary pouches, a plurality of primary valve chambers extending continuously throughout the length of the piano and immediately to the rear of said main suction chamber, one for each horizontal row of secondary valves and in communication with all of the pouch ports for such row, a primary valve for controlling tlie communication of each secondary pouch port with a primary valve chamber, and a primary pouch port in communication with the tracker bar.

3. A pneumatic piano including a main suction chamber with valve chambers in the front wall thereof, a removable plate secured to said front wall over each valve chamber therein, said plate having upper and lower openings through it, a valve in said valve chamber opposite said upper opening in said plate, means mounted in connection with said plate and located in said upper opening for regulating said valve, a power pneumatic with the base thereof thickened in the rear portion which portion is provided with a passageway leading through it to the power pneumatic, and screws extending horizontally through said thickened portion of the base of the power pneumatic for securing the same against said plate and to said main suction chamber so that the passageway through the lower part of the power pneumatic will register with the lower opening in said plate and be in communication with the valve chamber and the secured end of said power pneumatic be below the other opening in said plate, whereby the means for adjusting the valve will be readily accessible.

In witness whereof, I have hereunto afiixed my signature in the presence of the witnesses herein named.

WILLIAM G. BETZ.

VVit-nesses:

GUS UTTERBERG, EMIL SWANSAN.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

